The subject invention is directed toward the art of tube couplings and, more particularly, to a device intended to prevent undesired loosening of a threadedly connected tube coupling.
The device of the invention is especially suited for use with union type couplings and will be described with reference thereto; however, the invention can be used with other types of couplings including couplings constituted as an integral part of a flow device such as a valve.
One commonly used type of tube coupling comprises male and female body components joined by cooperating threads that permit connection and disconnection by relative rotation about the tubing centerline (see, for example, U.S. Pat. Nos. 5,135,269 and 5,066,051). The conditions to which the connected coupling is subjected can sometimes, over a period of time, cause loosening and resultant leakage. Although this rarely happens with a properly made-up, fully torqued fitting, in certain environments and when handling certain fluids, any possibility of leakage cannot be tolerated.
Many different types of lock devices have been proposed in the prior art for the prevention of random, undesired loosening of such couplings. However, these prior art devices have generally suffered from one or more disadvantages or defects. For example, certain prior art lock designs require installation prior to coupling makeup, and retro-fitting is not possible without system disassembly. With certain other designs, it has sometimes been necessary to locate the coupling components in a particular aligned relationship before the devices will function properly.